just a warning the latest patch broke the new vegas version of archive invalidation. to get mod to work with the latest patch you have to use the manual(FO3) version of archive invalidation. at least until the mod maker for the NV version updates it. also if you load the archiveinvalidation bsa before the new vegas ones it will crash the game. theres a workaround in the nexus forums tho. just a heads up.

Download the manual version of ArchiveInvalidation Invalidated: www.fallout3nexus.com/downloads/file.php?id=944 and follow the steps in the readme. It's really simple and takes no brain. If you launch the game with the launcher then the ini file you have to edit is Fallout_default.ini located in the install folder "Steam\steamapps\common\fallout new vegas"

*EDIT*As of the new patch 1.2.0.285 you have to rename the file into something that starts with "Fallout -" ex. "Fallout - ArchiveInvalidation.bsa" or "Fallout - a.bsa". Just remember to make it reflect the name change in ini file too.